mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
synced 2025-12-28 06:44:36 -05:00
9f048fa487
Depending on the particular CPU implementation a TLB shutdown may occur
if multiple matching entries are detected upon the execution of a TLBP
or the TLBWI/TLBWR instructions. Given that we don't know what entries
we have been handed we need to be very careful with the initial TLB
setup and avoid all these instructions.
Therefore read all the TLB entries one by one with the TLBR instruction,
bypassing the content addressing logic, and truncate any large pages in
place so as to avoid a case in the second step where an incoming entry
for a large page at a lower address overlaps with a replacement entry
chosen at another index. Then preinitialize the TLB using addresses
outside our usual unique range and avoiding clashes with any entries
received, before making the usual call to local_flush_tlb_all().
This fixes (at least) R4x00 cores if TLBP hits multiple matching TLB
entries (SGI IP22 PROM for examples sets up all TLBs to the same virtual
address).
Signed-off-by: Maciej W. Rozycki <macro@orcam.me.uk>
Fixes: 35ad7e1815 ("MIPS: mm: tlb-r4k: Uniquify TLB entries on init")
Cc: stable@vger.kernel.org
Reviewed-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Tested-by: Jiaxun Yang <jiaxun.yang@flygoat.com> # Boston I6400, M5150 sim
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.